Mixing apparatus having plural eductors



May 4, 1965 s. A. HAYES MIXING APPARATUS HAVING PLURAL EDUcToRs Filed April 3, 1963 United States Patent Gtlce 3,181,797` Patented May 4, 1965 3,181,797 MllXlNG APPARATUS HAVENG PLURAL EDUCTGRS Stanley A. Hayes, Arcadia, Calif., assigner to Hayes Spray Gun Company, Pasadena, Calif., a corporation of California Filed Apr. 3, 1963, Ser. No. 279,316 4 Claims. (Cl. Z39- 317) The present invention relates generally to mixing apparatus and in particular to apparatus for mixing a first liquid with a second liquid to provide a discharge stream having a desired ratio of first and second liquids.

Various types of apparatus for mixing a iirst liquid (water) with a second liquid (chemical solution) have been widely used for applying liquid chemicals such as fertilizers, fungicides, insecticides, and toxicants to trees, plants, lawns and agricultural crops. See, for example, my earlier Patents Nos. 2,381,589; 2,571,871; 2,592,896 and 2,388,445 (issued to l ames W. R. Stewart), directed to garden hose sprayers. Also see my copending applications Serial No. 199,216, filed May 4, 1962, now Patent No. 3,104,825 and Serial No. 153,797, iiled November 2l, 1961, now Patent No. 3,104,823 for Mixing Apparatus. These later applications relate primarily to power sprayers which are capable of applying germicides, bactericides and cleaning compounds to equipment, interiors and exteriors of buildings for cleaning purposes. The sprayers disclosed in my earlier patents and copending applications operate very satisfactorily in applying such chemicals. These sprayers include eductors which are generally designed to provide a predetermined ratio of water to chemical solution in the discharge stream. In the power sprayers, this ratio may be varied between two fixed values without changing the dimensions of the eductors. Furthermore, such sprayers generally provide a relatively high ratio of Water to chemical, for example, ofthe order of :1 to 69:1.

1t has been found desirable in certain applications to provide a mixing apparatus or power sprayer capable of providing a low ratio of water to chemical solution, for example, 1:1 and also highly desirable to provide a power sprayer in which this ratio can be readily changed to several different values.

The present invention provides a mixing apparatus which is capable of providing a low ratio of Water to educ.ed chemical solution and at the same time provide a very eflicient apparatus so that most of the potential energy in the water in the form of pressure may be converted into kinetic energy in the form of a high velocity stream to provide a long throw for the discharge stream for spraying trees, etc. The present invention also provides apparatus which is capable of providing several ditferent values of water to eductel chemical solution without the necessity of changing the solution strength of the source of the chemical or changing the dimensions of the eductors.

ln accordance with the present invention, a liquid mixing apparatus for mixing a second liquid (ie. chemical) with a first liquid (i.e. Water) from a source of the first liquid under pressure includes a first and second chemical eductor wherein each of the eductors defines an inlet passage, an aspiration chamber, and a cylindrical dirlusion passage arranged in series relationship in that order. First conduit means are provided for connecting the inlet passage of the first eductor to the source of the lirst liquid under pressure. Second and third conduit means are provided for connecting the aspiration chamber of the first and second eductors, respectively, to a source of the second liquid which may be at atmospheric pressure. Fourth conduit means are provided for connecting the diffusion passage of the first eductor to the inlet passage of the second eductor wherein the discharge stream from the diffusion passage of the first eductor is utilized to entrain the chemical solution through the second eductor.

In the preferred embodiment of the present invention, a third or power eductor including an inlet passage, a mixing chamber and a diffusion passage, is provided to educt the discharge stream from the second chemical eductor into a stream of the first liquid or Water. In this embodiment, the inlet passage of the third eductor is connected to the source of the first liquid and the diffusion passage of the second eductor is connected to the mixing chamber of the third eductor. Valves may be provided in the various conduit means so that anyone or more of the rst, second and third eductors are operative whereby the ratio of water to chemical solution may be readily changed.

The invention is described in more detail in reference to the accompanying drawing which is an elevation view of the preferred embodiment of the present invention partially in section.

Referring now to the drawing, there is illustrated a source of a first or carrier liquid indicated generally at 10. A pump 11 has an inlet 12 connected to the source of water and an outlet 13. The pump may be of any suitable type 4for pumping liquid from a low pressure to a relatively high pressure such as 500, or more, pounds per square inch (500 p.s.i.). A prime mover (not shown) may be used for driving the pump in a Well known manner. The outlet 13 of the pump is connected to an inlet 14 of a main conduit indicated generally at 15. The main conduit has an outlet 16 connected to a suitable spray nozzle 17 through which the water and chemical solution is discharged. A power eductor 18 of the jet pump type is disposed in the main conduit. The power (or third) eductor 18 includes a first bushing 2t) which defines stepped cylindrical bores 21 and 22 therethrough of decreasing diameter from inlet to outlet as illustrated. The power eductor 18 also includes a second bushing 25 which defines a cylindrical bore 26 therethrough of larger cross sectional area than the passage 22. The diffusion passage 26 functions to confine (or seal) the discharge stream from the passage 22 and to allow transfer ofV energy from the high velocity discharge stream to the entrained liquid. The bushings 20 and Z5 are spaced apart to provide a mixing chamber 27 which permits entrainrnent of the chemical solution into the Water stream flowing through the main conduit 15 as will be more fully described. The bores 21, 22 and 25 are preferably concentrically aligned.

A bypass conduit indicated generally at 39 has an inlet 31 connected to the inlet 14 of the main conduit and an outlet 32connected to the mixing chamber 27 of the power eductor 18. A first chemical jet pump eductor indicated generally at 34 is disposed in the bypass conduit and includes a first bushing 35 which defines cylindrical bores 36 and 37 therethrough of decreasing diameter from inlet to outlet as shown. The rst chemical eductor 3d also includes a second bushing 38 which defines cylindrical bores 39 and 49 therethrough of decreasing diameter from inlet to outlet. The bushings 35 and 3S are spaced apart to provide an aspiration chamber 42. A suitable suction conduit 43 is connected between the aspiration chamber 42 of the first chemical eductor and a source or container 44 of a second liquid such as a chemical solution (fertilizers, fungicides, insecticides, detergents, etc.). The smallest cylindrical bore 37 forms the inlet passage of the rst chemical eductor. This cylindrical inlet passage provides a high velocity discharge stream having a velocity substantially in the direction of ow to provide a solid integral discharge stream. The aspiration chamber 42 of the irst chemical eductor surrounds the discharge stream from the inlet passage 37 to permit the boundary of this stream to directly contact and entrain the chemical solution from the container 45.. The first passage 39 in the bushing 38 functions as a receiving passage for receiving the combined discharge stream from the passage 37 and the chemical solution cntrained thereby and directs this combined stream into the diffusion passage lh which seals or confines the stream and allows the transfer of energy from the high velocity discharge stream of water to the chemical solution from the container The ditiusion passage dit has a larger cross sectional area than the inlet passage 37.

A second chem'cal eductor' S@ is also disposed in the bypass conduit. The second eductor Sti includes an inlet passage il which is formed by the outlet portion of the diffusion passage all of the first chemical eductor 44. It should be noted, however, that the inlet passage of the second eductor t? need not be formed by a portion of the diffusion passage of the first chemical eductor. The second chemical eductor 5d includes a third bushing 52 which defines cylindrical bores :73 and Sli therethrough of decreasing diameter from inlet to outlet. The third bushing 52 is spaced from the bushing 38 to provide an aspiration chamber 55. The passage 53 ceiving passage for receiving the discharge stream from the passage and directs it into the dillusion passage 5f.- for confining the discharge stream from the passage 49 to allow transfer of energy from the high velocity discharge stream to the chemical solution from the container S2. A second chemical or suction conduit 56 is connected between the aspiration chamber 5S of the second chemical eductor 5t? and the source 4d of the second liquid. The cylindrical passage formed in the bushings 35, 3S and 52 are concentrically aligned. The diflusion passage 4l) of the first chemical eductor has a larger cross sectional area than the inlet passage Ti. and a smaller cross sectional area than the passage 54 of the second chemical eductor Sil.

lf it is desiredto provide a proportioning sprayer, that is a sprayer which is capable of providing a substantially constant ratio of water to educted chemical with varying inlet water pressures, it is necessary that the diffusion passages 4l) and 54 he substantially cylindrical, that is, cylindrical or having a taper of less than a 3 included angle and have a length at least equal to their diameter and preferably several times their diameter.

A first chemical valve 60 is provided in the suction conduit 43 and a second valve 6l is provided in the suction conduit 56 to control the flow of chemical solution through the suction conduits as will be more fully described. A bypass conduit valve 62 is connected in a bypass conduit between the inlet 3l thereof and the first chemical eductor 34 to control the iiow of the first liquid through the chemical eductor. A main conduit valve 63 is connected between the inlet 14 of the main conduit 15 and the power eductor i8 to control the flow of water through the power eductor.

In operation, water is discharged from the pump l1 at a high pressure, for example 500 p.s.i., and flows through the main conduit and the power eductor 1S. Water also iiows through the bypass conduit 36 due to the restriction imposed by the inlet passage 22 of the power eductor 18. The water flowing through the bypass conduit passes through the first and second chemical eductors 34- and 59 creating a partial vacuum in the aspiration chambers 42 and 55 which lifts chemical solution from the container 42 into the aspiration chambers 42 and 55 where it is entrained in the water stream. For eXample, the discharge stream of water from the inlet passage 37 of the first chemical eductor 34 entrains a predetermined ratio of chemical solution from the container 44. rthe cornbined water and chemical leaving the aspiration chamber 42 of the first chemical eductor is conlined or sealed in l?! K i.

the diffusion passage tti and then discharged into the aspiration chamber 55 of the second chemical eductor Sil. This discharge stream flowing into the aspiration chamber S5 of the second chemical eductor is conlined by the diffusion passage 54 of the eductor Sil and creates a partial Vacuum in the aspiration chamber' 55 which entrains chemical solution from the container 44. Thus the discharge stream from the diilusion passage 54 into the bypass conduit 3i? includes water lfrom the source lll and chemical solution flowing through the suction conduits d3 and 56. The water and chemical solution passing through the bypass conduit Bril is forced into the mixing chamber 27 of the power eductor 1S where it is entrained with the water stream .discharged from the inlet passage 22. The diffusion passage of the power eductor 1S allows the transfer of energy from the high velocity stream discharged from the inlet passage 22 to the stream passing through the bypass conduit 30. As a result, the stream leaving the diffusion passage 26 is a completely mixed high velocity stream which is then discharged from the nozzle 17 to the plants, trees, shrubs, etc., to be treated. The overall ratio of water to chemical solution of the discharge stream from the nozzle i7 is dependent upon the ratio of operation of the two chemical eductors and the power eductor. This ratio is the flow rate of the driving water from the source 1t) to the educted chemical solution from the container 44. 'lie material balance of these streams of liquid results in the following equation that relates the ratio of the individual eductors during operation to the overall ratio of the water to chemical solution leaving the nozzle 17.

Yinlaat 1er-R2 RD"R3+R1+R2+1+R1+R2+1 (A) Where:

R0=the ratio of the first liquid (water) to the second liquid (chemical solution) discharged from the nozzle 17;

R1=the ratio of the driving liquid flowing through the inlet passage to educted liquid flowing through the suction conduit of the first chemical eductor;

R2=the ratio of the driving liquid flowing through the inlet passage to educted liquid flowing through the suction conduit of the second chemical eductor;

R3=the ratio of the driving liquid flowing through the inlet passage of the power eductor to educted liquid flowing through the bypass conduit.

lf it is desired to operate only one of the chemical eductors with the power eductor then the following formula applies:

R0=R3+R-R3+R1 (B) Where Rl=the ratio of the driving liquid flowing through the inlet passage to the educted liquid ilowing through the suction conduit of the chemical eductor in operation.

if it is desired to operate only the two chemical eductors, then the following formula applies:

The above equations illustrate that R0 can be readily changed by controlling the Valves 60, 6l, 62 and 63. For example, the lowest `ratio of water to chemical is obtained by closing the Valve 63 and opening the valves 60, 61 and 62 so that the total discharge stream from the nozzle 17 is the stream flowing through the bypass conduit 36 with both chemical eductors in operation. A different ratio of R0 can be obtained by closing the valve 6l) so that only the second chemical eductor 50 is in operation. Either of the chemical eductors can be operated with or without the power eductor, and of course, both chemical eductors can be operated in conjunction with the power eductor 13.

The mixing .apparatus of the present invention has been employed to provide overall ratio R0 of approximately 1:1, that is one part of educted chemical solution to one part of water. To provide this type of operation it is preferable that the ratios (R1 and R2) of the first and second chemical eductors be approximately 2:1 (two to one). As shown by the above Formula C when this is the case, the ratio R is equal to 4/ 5 which means that for each four parts of discharged water there are five parts of educted chemical.

There has thus been disclosed a highly efficient mixing apparatus for mixing a second liquid with a carrier stream of a first liquid in which the proportion of the educted second liquid may be high compared to the driving stream of the first liquid and in which the ratio of the second liquid to the first liquid may be readily changed.

I claim: i

1. In a liquid mixing apparatus for mixing a second liquid with a first liquid from a source of the first liquid under pressure, the combination which comprises first and second eductors, each of the eductors having an inlet passage, an aspiration chamber and a diffusion passage arranged in series 'relationship in that order, conduit means for connecting the inlet passage of the first eductor to the source of the first liquid, conduit means for connecting the diffusion passage of the first eductor to the inlet passage of the second eductor and conduit means for connecting the aspiration chamber of each of the eductors to a source of the second liquid, the diffusion passage of the first eductor having a larger cross sectional area than the inlet passage of the first eductor, the diffusion passage of the second eductor having a larger cross sectional area than the inlet passage of the second eductor and the diffusion passage of the second eductor having a larger cross sectional area than the diffusion passage of the first eductor.

2. In a mixing apparatus as defined in claim 1 wherein the diffusion passages of each of the first and second eductors is substantially cylindrical and has a length at least equal to its diameter, and further including valve means disposed in the conduit means connecting the aspiration chambers of each of the eductors to the source of the second liquid for controlling the flow of the second liquid therethrough.

3. A mixing apparatus for mixing a second liquid with a first liquid comprising a pump having an inlet and an outlet, the inlet of the pump being connected to the source of the first liquid, a main conduit having an inlet and an Outlet, a bypass conduit having an inlet and outlet, means connecting the inlet of the main and bypass conduits to the outlet of the pump, first and second eductors disposed in the bypass conduit, each of the first and second eductors having an inlet passage, an aspiration chamber and a cylindrical diffusion passage connected in series in that order, the diffusion passages of each of the first and second eductors having a larger cross sectional area than the inlet passage of the respective eductor and a length at least equal to the diameter thereof, the diffusion passage of the second eductor having a larger cross sectional area than the diffusion passage of the first eductor, the diffusion passage of the first eductor being connected to the inlet passage of the second eductor, first conduit means for connecting the aspiration chamber of the first ed-uctor to a source of the second liquid, second conduit means for connecting the aspiration chamber of the second eductor to the source of the second liquid, a third eductor disposed in the main conduit and having an inlet passage, a mixing chamber and a diffusion passage connected in series in that order, the outlet of the bypass conduit being connected to the mixing chamber of the third eductor and a nozzle connected to the outlet of the main conduit to receive the discharge stream issuing from the diffusion passage of the third eductor.

4. The mixing apparatus as defined in claim 3 including a valve disposed in each of the first and second conduit means for controlling the flow of the second liquid into the first and second eductors, a valve disposed in the bypass conduit between the first eductor and the inlet thereof for controlling the flow of the first liquid through the bypass conduit and a valve disposed in the main conduit between the third eductor and the inlet of the main conduit for controlling the flow of the first liquid through the main conduit into the third eductor.

References Cited by the Examiner UNITED STATES PATENTS 2,953,160 9/ 60 Brazier IS7-599.1 3,103,312 9/ 63 Damrow 239-304 3,104,823 9/ 63 Hayes 239-407 3,104,825 9/ 63 Hayes 239-407 3,106,345 10/ 63 Wukowitz 239-344 3,109,594 l 1/ 63 Pletcher 239-422 LOUIS J. DEMBO, Primary Examiner, EVERETI` W. KIRBY, Examiner, 

1. IN A LIQUID MIXING APPARATUS FOR MIXING A SECOND LIQUID WITH A FIRST LIQUID FROM A SOURCE OF THE FIRST LIQUID UNDER PRESSURE, THE COMBINATION WHICH COMPRISES FIRST AND SECOND EDUCTORS, EACH OF THE EDUCTORS HAVING AN INLET PASSAGE, AN ASPIRATION CHAMBER AND A DIFFUSION PASSAGE ARRANGED IN SERIES RELATIONSHIP IN THAT ORDER, CONDUIT MEANS FOR CONNECTING THE INLET PASSAGE OF THE FIRST EDUCTOR TO THE SOURCE OF THE FIRST LIQUID, CONDUIT MEANS FOR CONNECTING THE DIFFUSION PASSAGE OF THE FIRST EDUCTOR TO THE INLET PASSAGE OF THE SECOND EDUCTOR AND CONDUIT MEANS FOR CONNECTING THE ASPIRATION CHAMBER OF EACH OF THE EDUCTORS TO A SOURCE OF THE SECOND LIQUID, THE DIFFUSION PASSAGE OF THE FIRST EDUCTOR HAVING A LARGER CROSS SECTIONAL AREA THAN THE INLET PASSAGE OF THE FIRST EDUCTOR, THE DIFFUSION PASSAGE OF THE SECOND EDUCTOR HAVING A LARGER CROSS SECTIONAL AREA THAN THE INLET PASSAGE OF THE SECOND EDUC- 